125 lines
3.6 KiB
C
125 lines
3.6 KiB
C
/*-
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* Copyright (c) 2008-2010 Rui Paulo <rpaulo@FreeBSD.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/types.h>
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#include <elf.h>
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#include <bootstrap.h>
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#if defined(__aarch64__) || defined(__amd64__)
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#define ElfW_Rel Elf64_Rela
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#define ElfW_Dyn Elf64_Dyn
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#define ELFW_R_TYPE ELF64_R_TYPE
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#define ELF_RELA
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#elif defined(__arm__) || defined(__i386__)
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#define ElfW_Rel Elf32_Rel
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#define ElfW_Dyn Elf32_Dyn
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#define ELFW_R_TYPE ELF32_R_TYPE
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#else
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#error architecture not supported
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#endif
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#if defined(__aarch64__)
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#define RELOC_TYPE_NONE R_AARCH64_NONE
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#define RELOC_TYPE_RELATIVE R_AARCH64_RELATIVE
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#elif defined(__amd64__)
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#define RELOC_TYPE_NONE R_X86_64_NONE
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#define RELOC_TYPE_RELATIVE R_X86_64_RELATIVE
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#elif defined(__arm__)
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#define RELOC_TYPE_NONE R_ARM_NONE
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#define RELOC_TYPE_RELATIVE R_ARM_RELATIVE
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#elif defined(__i386__)
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#define RELOC_TYPE_NONE R_386_NONE
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#define RELOC_TYPE_RELATIVE R_386_RELATIVE
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#endif
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void self_reloc(Elf_Addr baseaddr, ElfW_Dyn *dynamic);
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/*
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* A simple elf relocator.
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*/
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void
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self_reloc(Elf_Addr baseaddr, ElfW_Dyn *dynamic)
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{
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Elf_Word relsz, relent;
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Elf_Addr *newaddr;
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ElfW_Rel *rel;
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ElfW_Dyn *dynp;
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/*
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* Find the relocation address, its size and the relocation entry.
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*/
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relsz = 0;
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relent = 0;
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for (dynp = dynamic; dynp->d_tag != DT_NULL; dynp++) {
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switch (dynp->d_tag) {
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case DT_REL:
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case DT_RELA:
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rel = (ElfW_Rel *)(dynp->d_un.d_ptr + baseaddr);
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break;
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case DT_RELSZ:
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case DT_RELASZ:
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relsz = dynp->d_un.d_val;
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break;
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case DT_RELENT:
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case DT_RELAENT:
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relent = dynp->d_un.d_val;
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break;
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default:
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break;
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}
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}
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/*
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* Perform the actual relocation. We rely on the object having been
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* linked at 0, so that the difference between the load and link
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* address is the same as the load address.
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*/
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for (; relsz > 0; relsz -= relent) {
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switch (ELFW_R_TYPE(rel->r_info)) {
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case RELOC_TYPE_NONE:
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/* No relocation needs be performed. */
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break;
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case RELOC_TYPE_RELATIVE:
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newaddr = (Elf_Addr *)(rel->r_offset + baseaddr);
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#ifdef ELF_RELA
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/* Addend relative to the base address. */
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*newaddr = baseaddr + rel->r_addend;
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#else
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/* Address relative to the base address. */
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*newaddr += baseaddr;
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#endif
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break;
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default:
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/* XXX: do we need other relocations ? */
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break;
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}
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rel = (ElfW_Rel *)(void *)((caddr_t) rel + relent);
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}
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}
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